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Java > Open Source Codes > org > infohazard > maverick > view > DocumentViewFactory


1 /*
2  * $Id: DocumentViewFactory.java,v 1.7 2003/10/22 11:13:49 thusted Exp $
3  * $Source: /cvsroot/mav/maverick/src/java/org/infohazard/maverick/view/DocumentViewFactory.java,v $
4  */
5
6 package org.infohazard.maverick.view;
7
8 import javax.servlet.ServletConfig JavaDoc;
9
10 import org.infohazard.maverick.flow.ConfigException;
11 import org.infohazard.maverick.flow.View;
12 import org.infohazard.maverick.flow.ViewContext;
13 import org.infohazard.maverick.flow.ViewFactory;
14 import org.infohazard.maverick.util.XML;
15 import org.jdom.Element;
16
17 /**
18  * <p>
19  * Factory for building JSP, Velocity, and other resource-based views which
20  * place the model bean in one of the servlet attribute collections and
21  * use the RequestDispatcher to forward to the actual content.
22  * This is also used for static documents.
23  * </p>
24  * <p>
25  * This factory has certain options which can be defined when
26  * declaring the factory. The defaults are shown here:
27  * </p>
28  * <pre>
29  * &lt;view-factory type="document" provider="org.infohazard.maverick.view.DocumentViewFactory"&gt;
30  * &lt;default-bean-name value="model"/&gt;
31  * &lt;/view-factory&gt;
32  * </pre>
33  * <ul>
34  * <li>
35  * <b>default-bean-name</b> - If no "bean" attribute is specified
36  * for individual views, this is the key which will be
37  * used for placing the model in an attribute collection.
38  * </li>
39  * </ul>
40  * <p>
41  * The options for an individual view are like this:
42  * </p>
43  * <pre>
44  * &lt;view type="document" path="blah.jsp" scope="request" bean="model"/&gt;
45  * </pre>
46  * <p>
47  * Scope can be one of <code>request</code>, <code>session</code>,
48  * <code>application</code>. The default is <code>request</code>.
49  * </p>
50  * <p>
51  * The default model name is specified on the factory, or "model"
52  * if nothing is defined.
53  * </p>
54  * <p>
55  * Document views can have transforms by specifying a
56  * "<code>transform</code>" child element.
57  * </p>
58  */
59 public class DocumentViewFactory implements ViewFactory
60 {
61     /**
62      * The default attribute name for the "model" object ["model"].
63      */
64     protected static final String JavaDoc DEFAULT_DEFAULT_BEAN_NAME = "model";
65
66     /**
67      * The XML attribute name to set a default "model" object name
68      * ["default-bean-name"].
69      *
70      */
71     protected static final String JavaDoc ATTR_DEFAULT_BEAN_NAME = "default-bean-name";
72
73     /**
74      * <p>
75      * The XML attribute name to specify the name for the "model" object
76      * ["bean"].
77      * <p>
78      * <p>
79      * The default attribute setting would be <code>bean="model"</code>.
80      * </p>
81      */
82     protected static final String JavaDoc ATTR_BEAN_NAME = "bean";
83
84     /**
85      * <p>
86      * The XML attribute name to specify the scope in which to store the
87      * "model" object ["scope"].
88      * </p>
89      * <p>
90      * The default attribute setting would be <code>scope="request"</code>.
91      * </p>
92      */
93     protected static final String JavaDoc ATTR_SCOPE = "scope";
94
95     /**
96      * <p>
97      * The XML attribute value to specify "global" or "application" scope.
98      * ["application"].
99      * An "model" object set to this scope is available to the entire
100      * application.
101      * </p>
102      */
103     protected static final String JavaDoc SCOPE_APP = "application";
104
105     /**
106      * <p>
107      * The XML attribute value to specify "client" or "session" scope.
108      * ["session"].
109      * An "model" object set to this scope is available to every request made
110      * by the same client during this application session.
111      * </p>
112      */
113     protected static final String JavaDoc SCOPE_SESSION = "session";
114
115     /**
116      * <p>
117      * The XML attribute value to specify "thread" or "request" scope.
118      * ["request"].
119      * An "model" object set to this scope is available to only within the
120      * thread of the current request.
121      * </p>
122      */
123     protected static final String JavaDoc SCOPE_REQUEST = "request";
124
125     /**
126      * <p>
127      * Property to hold the default name of the "model" object for this
128      * factory instance ["model"].
129      * </p>
130      */
131     protected String JavaDoc defaultBeanName = DEFAULT_DEFAULT_BEAN_NAME;
132
133     /**
134      * <p>
135      * Initialize this factory instance by initializing the
136      * {@link #dispatchedViewFact} property and the {@link #defaultBeanName}
137      * property.
138      * </p>
139      * @param factoryNode Element
140      * @param servletCfg ServletConfig
141      * @throws ConfigException
142      */
143     public void init(Element factoryNode, ServletConfig JavaDoc servletCfg) throws
144       ConfigException
145     {
146         if (factoryNode != null)
147         {
148             String JavaDoc value = XML.getValue(factoryNode, ATTR_DEFAULT_BEAN_NAME);
149             if (value != null && value.length() > 0)
150                 this.defaultBeanName = value;
151         }
152     }
153
154     /**
155      * @param viewNode Element
156      * @return View
157      * @throws ConfigException
158      * @see ViewFactory#createView(Element)
159      */
160     public View createView(Element viewNode) throws ConfigException
161     {
162         String JavaDoc beanName = XML.getValue(viewNode, ATTR_BEAN_NAME);
163         if (beanName == null)
164             beanName = this.defaultBeanName;
165
166         String JavaDoc scope = XML.getValue(viewNode, ATTR_SCOPE);
167
168         // Provide different implementations of setAttribute depending on scope
169 if (SCOPE_APP.equals(scope))
170         {
171             return new DocumentView(beanName) {
172                 protected void setAttribute(ViewContext vctx) {
173                     vctx.getServletContext().setAttribute(this.beanName, vctx.getModel());
174                 }
175             };
176         }
177         else if (SCOPE_SESSION.equals(scope))
178         {
179             return new DocumentView(beanName) {
180                 protected void setAttribute(ViewContext vctx) {
181                     vctx.getRequest().getSession().setAttribute(this.beanName, vctx.getModel());
182                 }
183             };
184         }
185         else if (SCOPE_REQUEST.equals(scope) || scope == null)
186         {
187             return new DocumentView(beanName) {
188                 protected void setAttribute(ViewContext vctx) {
189                     vctx.getRequest().setAttribute(this.beanName, vctx.getModel());
190                 }
191             };
192         }
193         else
194         {
195             throw new ConfigException("Illegal scope specified: " + XML.toString(viewNode));
196         }
197     }
198 }
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